Gramophone sound box & record questions - UK Vintage Radio Repair and Restoration Discussion Forum

1100 man · 5th Nov 2019, 12:00 am

I recently bought a Decca 75 suitcase style gramophone which is built along very similar lines to the HMV 101.

Mechanically it works fine but the sound is rather 'harsh' and distorts on the loud bits. Even with a 'soft tone' needle, it's insanely loud. The sound quality from the HMV 101 was definitely nicer!

I dismantled the sound box to see what was in there and if the rubber had gone hard. This uses what looks like a thin Aluminium diaphragm (I think the HMV used a Mica one?) Both the rubber rings in the picture still seem pliable, but the rubber insulating ring between the mounting ring & sound box body is very hard.

Is there much difference in sound quality between different types & construction of soundboxes? Will the hard rubber between the mounting ring & body have an effect?

Secondly, the question of different types of records. I believe these players are better with earlier acoustically recorded records rather than later electrically recorded ones?

Some of the obviously later records I've tried seem even louder and tend to overload the soundbox.

I presume there is no easy way to tell what era a record comes from as they don't seem to carry production dates. I guess the design of the label itself will give the biggest clues to those that have the experience!

As you can tell, I'm a gramophone 'newbie', but after repairing the HMV 101 last year, I fell under the spell of these fascinating machines and would like to find out more about them.

This machine is dated 1934, so the best part of 86 years old!

Many thanks
Nick

dalgwcobl · 6th Nov 2019, 12:51 am

I would avoid any records that were produced from the late forties onwards, such as Decca FFRRs, which had a very high modulation level and were designed to be played on more modern lighter-weight electric pickups. Older red-label 10" and 12" HMVs and Brunswicks work well on my HMV101.
As you've got the sound box apart, I'd replace the suspension rubbers anyway. It is important to get the pivot screws set correctly so that the fulcrum piece from the needle is perfectly aligned with the centre of the diaphragm.
As you have found out, these gramophones are LOUD! A pair of socks, stuffed progressively into the horn, are a makeshift volume control, as in "put a sock in it"!

astro63 · 6th Nov 2019, 2:21 pm

like previous post are the sound box rubbers, that russet/ reddish and the white nice and soft and stretchy not hard, if they are there is people online where you can buy the rubber for it or someone on here will have a link to a suppler

5th Nov 2019, 12:00 am	#1
1100 man Octode Join Date: Apr 2016 Location: Ventnor, Isle of Wight, & Great Dunmow, Essex, UK. Posts: 1,377	Gramophone sound box & record questions I recently bought a Decca 75 suitcase style gramophone which is built along very similar lines to the HMV 101. Mechanically it works fine but the sound is rather 'harsh' and distorts on the loud bits. Even with a 'soft tone' needle, it's insanely loud. The sound quality from the HMV 101 was definitely nicer! I dismantled the sound box to see what was in there and if the rubber had gone hard. This uses what looks like a thin Aluminium diaphragm (I think the HMV used a Mica one?) Both the rubber rings in the picture still seem pliable, but the rubber insulating ring between the mounting ring & sound box body is very hard. Is there much difference in sound quality between different types & construction of soundboxes? Will the hard rubber between the mounting ring & body have an effect? Secondly, the question of different types of records. I believe these players are better with earlier acoustically recorded records rather than later electrically recorded ones? Some of the obviously later records I've tried seem even louder and tend to overload the soundbox. I presume there is no easy way to tell what era a record comes from as they don't seem to carry production dates. I guess the design of the label itself will give the biggest clues to those that have the experience! As you can tell, I'm a gramophone 'newbie', but after repairing the HMV 101 last year, I fell under the spell of these fascinating machines and would like to find out more about them. This machine is dated 1934, so the best part of 86 years old! Many thanks Nick Attached Thumbnails

6th Nov 2019, 12:51 am	#2
dalgwcobl Pentode Join Date: Dec 2008 Location: Royston, Hertfordshire, UK. Posts: 131	Re: Gramophone sound box & record questions I would avoid any records that were produced from the late forties onwards, such as Decca FFRRs, which had a very high modulation level and were designed to be played on more modern lighter-weight electric pickups. Older red-label 10" and 12" HMVs and Brunswicks work well on my HMV101. As you've got the sound box apart, I'd replace the suspension rubbers anyway. It is important to get the pivot screws set correctly so that the fulcrum piece from the needle is perfectly aligned with the centre of the diaphragm. As you have found out, these gramophones are LOUD! A pair of socks, stuffed progressively into the horn, are a makeshift volume control, as in "put a sock in it"!

6th Nov 2019, 2:21 pm	#3
astro63 Pentode Join Date: Mar 2013 Location: Norfolk, UK. Posts: 248	Re: Gramophone sound box & record questions like previous post are the sound box rubbers, that russet/ reddish and the white nice and soft and stretchy not hard, if they are there is people online where you can buy the rubber for it or someone on here will have a link to a suppler